The present invention is directed to an improved truck for a skateboard, all-terrain board or scooter, and more particularly to a truck having two independently spring-loaded pivoting members.
Conventional skateboards utilize steering mechanisms known as trucks. Typically a truck is mounted near each end of the skateboard, and includes a pair of wheels at each end of its axles. The trucks provide some steering response, whereby when a skateboarder shifts weight laterally across the board the axle twists, causing the hoard to turn. The trucks also serve, by means of a suspension system, commonly urethane bushings, to resiliently resist the skater""s lateral tilt of the duck, thus stabilizing the board, and returning it to its normal position when the turn is completed. This lateral stability is crucial for both distance riding and aerial tricks where a firm platform is desired. Current tucks must sacrifice their ability to turn for lateral stability, thus becoming stiff and unresponsive when tightened sufficiently. Conversely, loosening the trucks so the board can turn easily makes it dangerously wobbly, especially at higher speeds. Furthermore, even in optimal conditions, the rate of turn provided by conventional trucks is very little.
Previous attempts have been made to design as truck with increased maneuverability. One method utilizes a truck having a trailing castor that provides the skateboard with a second axis of rotation is described in U.S. Pat. No. 5,522,620 to Pracas.
In this prior art device, the truck comprises a conventional truck mounted to a pivotal member. The pivotal member is coupled to the nose of the deck about a hearing member which rotates along a plane parallel to the direction of motion. A pair of stop members are shown that limit the pivotal movement between two extreme positions. Further, a locking member maybe engaged to stop any rotation, thus returning the truck to a conventional configuration.
Although the ""620 device provides a second pivot, the lateral plane of pivotal rotation merely provides the front of the skateboard with a side to side movement. Because the axis of rotation is parallel to the direction of motion, lateral weight slit fling does riot bear any leverage upon he pivotal member when the arm is near the center of its range. Further when the pivotal member rotates towards its extreme positions, the skaters"" lateral weight imposes exponentially more leverage upon the member causing overturning and loss of control. Additionally, the ""620 device tines not regulate the torsional movement of the trailing castor. A strong bias to center is desired when performing aerial tricks so as to provide a predictable and stable landing. Further, regulating the rotational movement by a spring system is also important to stabilize the truck at high speeds.
Accordingly, a need exists for an improved truck that provides the user with more control over the torsional movement of the pivoting member and being adjustable for users of varying needs.
The present invention provides an improved skateboard truck which pivots about two axes and provides a combination of adjustable lateral stability and enhanced turning abilities. Generally speaking, a tuck according to this invention comprises an axle having a pair of wheels mounted al opposite ends thereof. A shall extends through the center of the axle and is secured thereto on the side of the axle distal from the point of securing the truck to a skateboard. The truck further includes a resilient bushing circumferentially mounted on the shall on the side of the axle proximal to the point of securing the truck to the skateboard for providing a first pivot axis about the axle, and a swivel connected to the axle and adapted to be pivotally attached to the underside of the skateboard about a second pivot axis. The swivel and the bushing are ganged together to provide pivoting of a skateboard in two dimensions.
In a presently preferred embodiment of the invention the skateboard truck includes a base attachable to the underside of a skateboard and an arm carried by the base and rotatable relative to the base about a first axis. An axle having a pair of wheels mounted at opposite ends thereof is carried by the arm and the axle is rotatable relative to the arm about a second axis. A spring-loaded linkage is operatively connected between the base and the arm for limiting the rotational motion of the arm and biasing the arm towards a rest position aligned with the skateboard""s direction of movement.
The improved skateboard truck is preferably attached to the front of the skateboard, while a conventional truck is fastened to the rear. Because of the improved capabilities of the present invention the skateboarder is able to propel the skateboard by shifting the nose of the skateboard from side-to-side, lumber, the present invention enables the rider to smoothly navigate the front of the skateboard to-and-fro and complete sharp turns at a rider controlled rate. As such, the skateboard closely simulates the dynamics of a surfboard oil the water.